When photographers Zana Briski and Ross Kauffman set out to chronicle the lives of sex workers in the red-light district of Calcutta, they faced obstacles. They did not speak the language. No one wanted their illegal behavior captured on film. And when they appeared with their video cameras, prostitution disappeared.

Instead, they found a different story in the children of sex workers. They gave a handful of kids cameras and taught them how to use them. The interaction of the Western filmmakers and the young shooters turns into an amazing documentary. The youngsters' photographs are inspiring. Their lives are complicated. Growing up in crushing poverty, the girls are all but certain to end up like their mothers, selling their flesh for their daily rice. (The film never addresses whether the boys will be sold for sex.)

Zana and Ross try to rescue the kids by placing them in boarding schools in India. One boy, Avijit, is sent to Amsterdam to represent India in a worldwide kids-and-photography conference. Just before he is to leave (amid endless paper shuffling among bureaucrats to get him a passport), his mother is burned to death in their kitchen by her pimp. The boy loses interest in everything, and it takes all Zana's skills to get him to the conference and later to a boarding school.

The Calcutta kids' photos are organized into a show and then into a book being sold to raise money for Kids and Cameras (kids-with-cameras.org/kidsgallery).

The Westerners know they are working against a floodtide. But still they soldier on. They get a few of their flock into boarding schools. Some stay. Some return to the district.

The spirit of the kids is illuminating. But it's pretty clear most of them will end up repeating the cycle of their parents.